It has been known that at the time of onset of short-bowel syndrome, ulcerative colitis, diarrhea caused by antibiotics, dyspeptic diarrhea, or Crohn's disease, or after excision of a digestive tract and administration of an elemental diet, fermentation in the large intestine becomes abnormal, accompanied by high accumulation of lactic acid.
Since lactic acid is a strongly acidic substance and sparingly absorbed in the large intestine, once it becomes in an excess state, the inside of the large intestine is quickly acidified. In such a state, the lactic acid conversion function of bacteria and the epithelial cell function in absorption are inhibited thereby lowering the consumption of lactic acid. As a result, accumulation of lactic acid is accelerated and results in repetition of a vicious circle, which makes recovery from pathological conditions difficult.
Heretofore, in such an abnormal physiology of the colon, it has been usually to administer a pharmaceutical product of lactobacilli, bifidobacteria or enterococci, or to administer oligosaccharides to activate these bacteria.
These bacteria, however, are lactic acid bacteria in the broad sense, which produce lactic acid as a major product. Therefore, it is doubtful whether they are effective to cure diseases caused by abnormal accumulation of lactic acid.
On the other hand, butyric acid which is one of short-chain fatty acids is produced by normal fermentation in the large intestine and utilized selectively by the epithelium of the colonic mucosa. Though lactic acid is sparingly absorbed from the epithelial cell of the colonic mucosa and cannot be utilized as an energy source in the mucosal epithelial cells, butyric acid works as an energy source to stimulate the growth of the epithelial cells on the colonic mucosa and promote absorption of minerals and water.
Therefore, supply of not lactic acid but butyric acid is essential in order to develop soundly the function of the colonic mucosa.
In addition, it is known that the butyric acid content is decreased in the digestive tract in a patient suffering from colon cancer. On the other hand, it is known that butyric acid promotes differentiation of the cells of colon cancer to reduce the number of cancer cells; therefore, it can be said that increase of butyric acid in the digestive tract is advantageous in case of such a disease.
Thus, it cannot be said that a method for positively eliminating the state of accumulation of lactic acid and a technique for quickly converting lactic acid into a useful substance by using a lactic acid bacterium preparation or activator have been established. Moreover, materials used for the purpose of improving the internal environment of the intestine do not reduce hyperlactate production or help to generate butyric acid.
The present invention was made in view of the above-mentioned problems in the prior art. The purpose of the invention, accordingly, is to provide a method for quickly converting lactic acid into butyric acid in the intestine, and thus to alleviate pathological conditions due to abnormal accumulation of lactic acid and by increase of butyric acid make much more effective the prior means for improving the intestinal environment which aim to improve the intestinal environment and activate lactic acid bacteria.